using System;
using System.Collections.Generic;
using System.Text;

namespace System.Text
{
    public sealed class StringBuilder2 : IStringBuilder
    {
        readonly StringBuilder builder;

        public StringBuilder2() : this(new())
        {

        }

        public StringBuilder2(StringBuilder builder)
        {
            this.builder = builder;
        }

        IStringBuilder IStringBuilder<IStringBuilder>.Append(string? value)
        {
            builder.Append(value);
            return this;
        }

        public override string ToString() => builder.ToString();
    }
}
